Quick update for Ubuntu users planning to use Ubuntu 15.04: GTK 3.14 has landed in Ubuntu 15.04 Vivid Vervet. And of course, the default Ubuntu themes, Ambiance and Radiance, have been updated with GTK 3.14 support.

Furthermore, Nautilus, an application that wasn't updated in quite a while and was still at version 3.10, has been updated to version 3.14:

However, Nautilus isn't the only application that was updated to version 3.14 in Ubuntu 15.04 Vivid Vervet. A while back, GNOME Terminal (Ubuntu was using an ancient version - 3.6), GNOME Screenshot, GNOME Calculator and Evince were also updated to 3.14.

As for Ubuntu GNOME, well, GNOME Shell, GNOME Control Center / Settings Daemon are still at version 3.12 (along with most of the GNOME apps like Weather, Clocks, Bijiben and so on), but these will probably be updated to 3.14 as well, considering that there's still time, since Ubuntu / Ubuntu GNOME 15.04 is in alpha and it's scheduled for release in April, 2015.